防風構造物防鹽功效之風洞試驗

Abstract

This reserch was to investigate the effects on salt spray control and wind protection for different structures, including net, wall and Venetian-blinds. Simulating the wind field of boundry layer and salt spray distribution with the wind tunnel, we analyzed the relationships between various windbreaks and control effects. The effects are estimated from PIS(50%) for salinity and PI(50%) for velocity. The results were concluded as follows: 1.The boundry layer of earth surface was simulated by the conditions of 8.1m/s wind velocity and the injecting sea water rate of 1 cm^3/sec in wind tunnel.2.It exists a quadratic relationship between the effect of the salt spray control and the density of windbreak net. 3.The logarithm of effect on windbreak is direct proportion to the effect of salt spray control. 4.In Venetian-blinds windbreak,the effect of salt spray control decreased with the increase of blade angle in the constant partition between two blades. 5.In general, the best wind protect is the net at the 70% density and the salt effect is the Venetian-blinds at the angle 45,partition 1 cm.

本研究係於風洞內模擬大氣邊界層內流場及近地大氣中鹽分分佈情形，探 討各種密度之防風網、不同型式之百葉防風柵及防風牆等構造物的防風、 防鹽效果，並分析防風與防鹽兩者間相互關係，以祈未來在現地提供最佳 防風、防鹽構造物設計之參考。文中防風、防鹽效果分別採相對風速50% 、相對鹽分50%下所涵蓋之面積，作為評估之依據。試驗結果分述如下： 一、風洞試驗於1cm^3/sec注入海水時，以風速8.1m/s模擬現地風場及鹽 分分佈，其結果 最為接近。 二、防風網之密度與其防鹽效果，具有二次函數之關係。 三、防風構造物之防風效果的對數值與防鹽效果成正比。 四、葉片間距相同之百葉防風柵，其防鹽效果隨著葉片角度的增加而減小 。 五、防風效果以密度70%防風網最佳；防鹽效果以葉片間 距1.0cm、葉片角度45 °之百葉 防風柵最佳。